The present invention is directed to a plasma treatment apparatus for parallel workpiece treatment. Attention is drawn to the following prior art: DE-U-91 13 860, EP-A-0 381 338 (corresponding to JP-A-2 297 925, U.S. Pat. Nos. 5,112,641 and 5,217,340) and DATABASE WPI, Derwent Publications Ltd., London, GB; AN 90-265161 C35, and JP-A-2 186 628.
It is an object of the present invention to provide a plasma treatment apparatus by which a predetermined number of workpieces may be parallel processed, whereby the number of operating cycles for such treatment is minimalized so as to reach optimal short throughput times with optimal low handling effort. Thereby, minimalizing handling effort results in an accordingly low constructional effort for the overall apparatus and in an accordingly low effort for controlling purposes of such an apparatus. As workpieces especially substrates shall be processed, i.e. workpieces which are at least substantially plate-shaped, plane or possibly bent.
Thus, the object of the present invention is to provide a plasma treatment apparatus with small footprint, enabling low manufacturing costs, especially for flat display panels as especially for flat active display panels, thereby especially for so called TFT display panels, which further allows high flexibility with respect to selection of different processing steps, allows use of a simple robot to load/unload the apparatus in ambient, and which furtherxe2x80x94and especiallyxe2x80x94allows high throughput.
This object is realised by an apparatus for vacuum plasma treatment comprising at least one treatment station with at least two substrate carriers stacked one above the other and in vertical alignment, further with at least two sealably closable handling openings vertically in mutual alignment and in horizontal alignment with said at least two carriers; a transport chamber communicating with said at least one station via said handling openings and comprising a transport robot being rotatable around a vertical axis and comprising at least two substrate supports extending horizontally and substantially aligned with said at least two carriers and being radially movable.
Thereby, the principle of parallel processing is strictly followed, not only for the mere substrate treatment, but also for substrate handling, i.e. for loading and unloading of the parallel arranged substrate carriers. This is realized, as mentioned, by the fact that the rotatable transport robot may simultaneously serve the carriers. With respect to the layout of plasma treatment facilities as may be implemented in the treatment station, we refer to the EP-A-0 221 812 and the EP-A-0 312 447 which are incorporated to the present description by reference.
Further, the concept of handling these substrates in a substantially horizontal position leads to a significant reduction with respect to constructional efforts and compared with handling in vertical position. This is true also with respect to hybrid forms in which workpiece handling switches from horizontal to vertical or vice-versa.
In one preferred embodiment of the inventive apparatus, the treatment station comprises at least two vacuum-tight separate treatment chambers with respectively one of said substrate carriers and one of said handling openings, especially for the application of deposition processes like PECVD.
In another, even more preferred embodiment the treatment station comprises at least two treatment compartments within a common vacuum chamber, whereby the treatment compartments within the common vacuum chamber communicate with the vacuum chamber by open gas flow communication or via pressure stages, which allow to maintain different pressures in the compartment and the vacuum chamber, especially for the application of etching processes like PE and RIE. Thus, in a most preferred embodiment the treatment station is formed by one common vacuum chamber with said at least two carriers therein. Further, in a preferred mode of the inventive apparatus, the treatment station comprises the same number of substrate carriers as the number of supports provided at the robot or an integer multiple of such support number and, as will be explained later on, transport and loadlock operation is based on parallel processing of a number of substrates equal to the number of supports at the robot. By parallel processing that number and especially just two substrates, thereby especially processing same in one common vacuum chamber, nevertheless with preferably two treatment compartments adjacent to each of the substrate carriers, there is provided a most compact, low footprint plant, also due to the fact that parallel processing occurs in vertical alignment. The preferred xe2x80x9cjust-twoxe2x80x9d concept gives optimum compromise of plant simplicity, high feed-through and simple handling from ambient.